This is an ORIGINAL cap screw that holds the forearm onto the actio slide of a 16 or 20 ga Winchester model 12, 16 gauge.shotgun. Note: This part can be near impossible to get off and many a forearm has been broken in the process. I will share a little seacret that has yet to fail me. The only way that I have found to remove the action slide cap screw (with out any damage or frustration) is with the Wyoming sight Drifter part number T740.